Emotional distress and control cognitions as mediators of the impact of chronic pain on disability

Objectives. To explore the hypothesized mediating effects of cognitions and emotional distress on che pain-disability relationship. Design. Pain (McGill Pain Questionnaire), disability (Oswestry Low Back Pain Disability Questionnaire), emotional distress (General Health Questionnaire 28) and Locus of Control (Multidimensional Health Locus of Control) were examined by MANOVA for differences between admission to a pain rehabilitation programme and follow-up and by correlation to examine inter-relationships. Stepwise multiple regressions rested for the significant predictors of disability on admission and follow-up and proportional change. Methods. Seventy-three patients met the criteria for inclusion (age between 16 and 65 years, low back pain for six months, English speaker). Fifty-four patients were available for follow-up. Patients attended a three-week programme based on cognitive behavioural principles. Data were collected by self-report on admission to the programme and at three-month follow-up. Results. At follow-up, disability, pain and emotional distress were all found to have improved. Admission, follow-up and proportional change scores showed no correlation between pain and disability at any stage. However, distress and internal Locus of Control (IHLC) were related to disability and distress was also related to pain. Multiple regressions showed chat IHLC and distress predicted disability on admission and follow-up. Distress predicted the proportional change in disability Conclusions. No direct relationship was found between pain and disability. It appeared that IHLC modified, and emotional distress mediated, the pain-disability relationship.